The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
A typical carrier assembly used in planetary gear sets includes a spider carrier welded to a carrier flange or shell. A plurality of pinions and pinion washers are supported for rotation within the spider carrier. The carrier spider must have a machined surface in order to accurately locate the pinion washers. However, the typical spider assembly has a plurality of legs or members that extend out from the surface. These legs can interfere with the machining process as they can obstruct the movement of the machining tool.
One conventional method of machining the surface of a cast or forged spider carrier is to employ a traditional milling operation to produce a machined surface. However, this process requires multiple milling machines arranged in parallel to produce sufficient quantities to meet typical production volumes. An alternate solution is to make the spider carriers using net forging. However, net forged spider carriers may have a surface flatness that consumes about 70% to 80% of the total tolerance allowed in the finished welded carrier assembly. This can impede can make it difficult to meet the dimensional criteria for finished carrier assemblies.
Accordingly, there is room in the art for a method of machining a surface of a spider carrier that has improved dimensional control of the finished carrier assembly and which reduces the cycle time and lowers the capital investment compared to traditional milling.